Updated on 2026-08-14

app/src/main/java/com/tangem/domain/cardReader/FW.java

@@ -0,0 +1,62 @@
+package com.tangem.domain.cardReader;
+
+import android.content.Context;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.tangem.util.Util;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
+
+public class FW {
+    private static JsonArray jaFirmwares=null;
+
+    public static boolean needInit() {
+        return jaFirmwares == null;
+    }
+
+    public static void Init(Context context) {
+        try(InputStream is=context.getAssets().open("fw_hashes.json")) {
+            try (InputStreamReader reader = new InputStreamReader(is, StandardCharsets.UTF_8)) {
+                JsonParser parser = new JsonParser();
+                jaFirmwares = parser.parse(reader).getAsJsonArray();
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static class VerifyCodeRecord
+    {
+        public String hashAlg;
+        public int blockIndex;
+        public int blockCount;
+        public byte[] challenge;
+        public byte[] digest;
+    }
+
+    public static VerifyCodeRecord selectRandomVerifyCodeBlock(String firmwareVersion) throws IOException {
+
+        for(int i=0; i<jaFirmwares.size(); i++) {
+            JsonObject jsVersion = jaFirmwares.get(i).getAsJsonObject();
+            if( jsVersion.get("fw").getAsString().equals(firmwareVersion) )
+            {
+                VerifyCodeRecord result=new VerifyCodeRecord();
+                result.hashAlg = "sha-256";
+                JsonArray jsHashes = jsVersion.get(result.hashAlg).getAsJsonArray();
+                result.challenge = Util.hexToBytes(jsVersion.get("challenge").getAsString());
+                int caseIndex= Util.byteArrayToInt(Util.generateRandomBytes(4))%jsHashes.size();
+                JsonObject jsRecord = jsHashes.get(caseIndex).getAsJsonObject();
+                result.blockIndex = jsRecord.get("block").getAsInt();
+                result.blockCount = jsRecord.get("count").getAsInt();
+                result.digest = Util.hexToBytes(jsRecord.get("digest").getAsString());
+                return result;
+            }
+        }
+        return null;
+    }
+}